Whistle



FIG. 1 is a perspective view of a whistle showing my new design.

FIG. 2 is a front view.

FIG. 3 is a side view.

FIG. 4 is a back view.

FIG. 5 is a top view.

FIG. 6 is a bottom view. 

The ornamental design for a whistle, as shown and described. 